Can't open mail on Mac

have you try booting in safe mode?

if not, I suggest you try it.

here’s how.

after you’re in safe mode, does Mail opens?

Start up your Mac in safe mode

Starting up your Mac in safe mode may help you diagnose problems with your Mac.

Note: To print these instructions, press Command-P.

1. On your Mac, choose Apple menu  > Shut Down.
2. After your Mac shuts down, wait 10 seconds, then press the power button.
3. Immediately after your Mac starts (some Mac computers play a startup sound), press and hold the Shift key.
4. Release the Shift key when you see the gray Apple logo and progress indicator.

To leave safe mode, restart your Mac again, but don’t press and hold any keys during startup.

GB201 Said:

"I cannot open my mail on my Mac. Help!"

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5 Thoughts on Troubleshooting Mail being Open

How to Open Mail:

A. Use Spotlight Search:

[Hold Down: command + press: spacebar] then type Mail

B. Add it as a Login Item:

See if it opens at login. Then, remove it as a login item. Ant try opening once more.

Go Here: Open Items Automatically when you Log In on Mac - Apple Support

C. Check Force Quit:

1. Go to: Apple menu
2. Click: Force Quit...
3. See: If Mail is Shown

D. [Hold Down: command + Press: Tab] Until Mail is selected.

E. Slide: Three finder to the left on the Trackpad. See if Mail opens

We can only help you if you can tell us something about how this happened. Did you change or add anything to your computer? Are you getting any messages? How are you trying to open Mail? Have you tried restarting the computer or done any diagnostics? Please click on the link below and read the information there, then you can respond. Thank you.

Writing an Effective Apple Support Communities Question - Apple Community

Can you get a screenshot of the double circle? It sounds like a notification badge, but I'd like to be sure of.

What version of Mail is it?

Mail-About Mail - please provide screenshot there.

see what to do If you can't open Mail on your Mac

If you try to open a version of the Mail app  that can’t be used on your Mac, an alert message is displayed.

Make sure the version of Mail you’re trying to open is located in the Applications folder. In the Finder , click Applications in the sidebar, then double-click Mail.

If the problem continues, contact Apple Support.

GB201 Said:

"I cannot open my mail on my Mac. Help!: Tried all of these. Didn't work.”

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A Few Thoughts:

A. Create a New Administrator User:

Does it now open? If so, it is likely something misconfigured in the current user. If not, then it’s a bug in the macOS. And reinstalling it has the intent on fixing issues such as with built in apps.

B. Reinstalling the macOS:

Sometimes, changes are made to your Mac (i.e. uninstalls), and then settings (i.e. for power), become manipulated, technically.

What Reinstalling the macOS does:

So, reinstalling the macOS with place moved items back to where they should be, and will replace damaged system files.

1. First, Back up your Mac:

Create a Time Machine backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong with the reinstall.

2. Then, Reinstall the macOS:

Nothing would be deleted. It's just that items that have become corrupted or deleted, would be replaced or reinstalled back to where they should be. Go Here: How to Reinstall macOS from macOS Recovery - Apple Support

C. Reinstalling the macOS Anew:

If that doesn’t work — Then reinstall the macOS anew (more on that later, if a reinstall does not work).

If the Safe Mode doesn't help, then we would suggest that you download, install and run the free app EtreCheck. Be sure to enable full disk access. it will generate a report of what's in your computer. Then post the report below under the "Attachment text" icon. That report will be most helpful in analyzing what may be happening.